Clumped-isotope-derived climate trends leading up to the end-Cretaceous mass extinction in northwestern Europe

<p>Paleotemperature reconstructions of the end-Cretaceous interval document local and global climate trends, some driven by greenhouse gas emissions from Deccan Traps volcanism and associated feedbacks. Here, we present a new clumped-isotope-based paleotemperature record derived from fossil bivalves from the Maastrichtian type region in southeastern Netherlands and northeastern Belgium. Clumped isotope data document a mean temperature of <span class="inline-formula">20.4±3.8</span> <span class="inline-formula">^∘</span>C, consistent with other Maastrichtian temperature estimates, and an average seawater <span class="inline-formula"><i>δ</i>¹⁸</span>O value of <span class="inline-formula">0.2±0.8 ‰</span> VSMOW for the region during the latest Cretaceous (67.1–66.0 Ma). A notable temperature increase at <span class="inline-formula">∼66.4</span> Ma is interpreted to be a regional manifestation of the globally defined Late Maastrichtian Warming Event, linking Deccan Traps volcanic CO<span class="inline-formula">₂</span> emissions to climate change in the Maastricht region. Fluctuating seawater <span class="inline-formula"><i>δ</i>¹⁸</span>O values coinciding with temperature changes suggest alternating influences of warm, salty southern-sourced waters and cooler, fresher northern-sourced waters from the Arctic Ocean. This new paleotemperature record contributes to the understanding of regional and global climate response to large-scale volcanism and ocean circulation changes leading up to a catastrophic mass extinction.</p>